SIGNIFICANCE OF THE ISOLATION OF CANDIDA SPECIES FROM RESPIRATORY SAMPLES IN CRITICALLY ILL, NON-NEUTROPENIC PATIENTS - AN IMMEDIATE POSTMORTEM HISTOLOGIC-STUDY

The diagnosis of pulmonary candidiasis is still controversial. We unde rtook a prospective study on 25 non-neutropenic, mechanically ventilat ed (> 72 h) patients who died in our ICU with the aim of assessing the incidence and significance of the isolation of Candida species from q uantitative cultures of immediate postmortem lung biopsies and differe nt respiratory sampling techniques. Immediate postmortem respiratory s amples (endotracheal aspirate, protected specimen brush [PSB], broncho alveolar lavage [BAL], blind biopsies [average 14/patient], and bilate ral bronchoscopically guided biopsies [two per patient]) were taken fr om all patients. Lung tissue specimens were histologically examined. R espiratory samples were classified as having Candida or otherwise. Ten (40%) patients had at least one pulmonary biopsy yielding Candida spp . Among these 10 patients with Candida isolates, only two had definite pulmonary candidiasis. A total of 470 microorganisms were isolated fr om 280 of 375 (77%) lung biopsy samples in all 25 patients. Candida sp ecies represented 9% (n = 40) of the isolates, corresponding to 10 pat ients (40%). In the 10 patients in whom Candida species was isolated f rom pulmonary biopsies, this was always associated with the isolation of the same microorganism from one of the sampling methods. Quantitati ve cultures of Candida species from different sampling methods correla ted well among each other but could not discriminate the presence from absence of Candida pneumonia. A logistic regression model adjusted fo r the presence of antibiotics, days of antibiotic treatment, mechanica l ventilation period, age, ARDS, parenteral nutrition, and gender did not show any independent risk factor for developing positive pulmonary samples for Candida species. The incidence of Candida isolation from pulmonary biopsies in critically ill mechanically ventilated, non-neut ropenic patients who die is high (40%). However, the incidence of defi nite Candida pneumonia was 8%. We also found that Candida colonization is uniform throughout the different lung regions, and that the presen ce of Candida in respiratory samples, independently of quantitative cu ltures, is not a good marker of Candida pneumonia in critically ill, n on-neutropenic, non-AIDS patients.